Heat exchanger



May 13, 1958 o. oLDBl-:RG ET AL 2,834,583

HEAT EXCHANGER Filed sept. 19', 1955 l :s sheets-sheet 1 ,l @im M 7?@ A. 5am berg HE May 13, 1958 o. OLDBERG ET A| 2,834,583

HEAT EXCHANGER Filed Sept. 19, 1955 3 Sheets-Sheet 2 @saar @lf/berg @Lf f HHHE May 13, 1958 o. OLDBERG ET AL 2,834,583 HEAT EXCHANGER Filed Sept. 19, 1955 `3 Sheets-Sheet 3 F 8 F' .L fob 50 b scar /dberg United States Patent y E HEAT EXCHANGER Oscar Oldberg, Birmingham, Mich., and Ray A. Sandberg, Waukegan, lli., assgnors to Houdaille Industries, Inc., Detroit, Mich., a corporation of Michigan Application September 19, 1955, SerialNo. 534,941 2 Claims. (CL' 257-262.16)

This invention relates to a fin and tube type heat ex-` changer and method of making the same.

It is an important object of the present invention to provide an improved method of making a iin and tube 'A type heat exchanger.

It is a further object of the present invention to provide a novel heat exchanger of the fin and tube type having means for retaining the tube with the fins which positively presses the tube into good heat exchange contact with the fins.

'It is a further object of the present invention to provide a novel fin and tube type heat exchanger construction which can employ serpentine tubing without any need for jointed return bends.

It is still another important object of the present invention to provide a novel and improved method for making a fin and tube type heat exchanger which affords improved heat transfer between the tube and the heat exchange fins.

In accordance with the features of the present invention, the heat exchange tubing is assembled in a series of notches, and elongated channel members are pressed into the notches to close the same, the channel members being placed under a predetermined tension during the assembly process as they are conformed to the periphery of the tubing to exert a positive pressure on the tubing urging the tubing against the end of the notches. More specifically, the channel members comprise a relatively at body portion having turned anges fat the longitudinal edges thereof which, as the body portion is conformed to the periphery of the tubing, are snapped into niches in the sides of the notches in such a manner as to retain the channel member in resilient tensoned condition to press the tubing against the ends of the notches.

Other and further important objects and features of the present invention will be apparent from the following disclosure in the specification and the accompanying drawings.

On the drawings:

Figure l is a side elevational view of a n and tube type heat exchanger in accordance with the present invention, the major number of the ns intermediate the ends of the heat exchanger being omitted for simplicity;

Figure 2 is a bottom plan view of the structure of Figure 1;

Figure 3 is a left end elevational view of the structure of Figure l;

Figure 4 is a view illustrating the manner in which the fins are formed from a flat blank;

Figure 5 is a cross sectional View taken generally along the line V-V of Figure 4;

Figure 6 is a side elevational view of a fin ready to be assembled with the tubing;

Figure 7 is an end elevational View of the structure of Figure 6;

Figure 8 is a fragmentary bottom plan view of the structure of Figure 6;

I A2,834,583 Patented May 13, 1958 Figure 9 is a side elevational View of a channel member in initial condition prior lto assembly with the fin and tubel structure to retain the tube with the fins;

Figure 10 is an end elevational view of the structure of Figure 9;

Figure 11 is a diagrammatic View illustrating a tool for pressing the channel member into the respective notches; and

Figure 12 illustrates the manner in which the turned anges of the channel member are snapped4 into engagement with niches at the sides of the tube receiving notches.

As shown on the drawings:

As seen in Figures 1, 2 and 3, the tube and fin heat exchanger of the present invention may, by Way of example, comprise a pair of serpentine tubes 10 and 11 having respective straight run portions 10a and 11a and respective connecting bend portions 10b and 11b. As seen in Figure l, the straight run portions have a multiplicity of fin plates 13 extending at generally right angles to the planes of the tube runs 10a and 11a and interconnected with the tubing. Specifically, as seen in Figure 3, the fin plates 13 each have a succession of notches 15 in one longitudinal edge 13a thereof and a series of notches 17 in an opposite longitudinal edge 13b. The notches are spaced along the length of the fin so as to receive the respective tube runs 10a and 11a, the notches 17 preferably being offset longitudinally from the notches 15. A tube length 20 may connect the last tube run of tubing 10 with the first run of tubing 11.

Bracket members 22 and 23 may have elongated slots such as 24 and 25 for receiving the respective return bends 10b and 11b, the brackets 22 and 23 having suitable ange means 22a and 23a for mounting of the heat exchanger.

For locking the tubing in the respective notches and for pressing the tubing into firm heat exchange relation to the fin plates, channel members 30 are provided each of which extends the length of one of the tubing runs 10a or 11a and has turned flanges 30a and 30h extending into niches 32 and 33 formed at the sides of each notch 15 and 17, the free ends of the flanges 30a and 3017 engaging shoulder portions 34 and 3S which face' the ends of the notches.

It will be understood that the fins are preferably uniformly spaced over the entire length of the tube runs between the brackets 22 and 23, and that the intermediate fins in Figure l and Figure 2 have been omitted for simplicity of illustration.

The manner of forming the fins 13 is illustrated in Figures 4 to 8. As illustrated in Figures 4 and 5, the fins may be formed from a flat sheet by stamping slots such as 40 and 41 along the respective longitudinal edges of the sheet, and also forming stiifening embossments such as 42, 43, 44 and 45 uniformly along the blank. The slots 40 and 41 have arcuate end edges such as 45 for conforming to the periphery of the tubing and have lateral recesses such as 46 for providing the niches 32, 33. The projections such as 47 at the mouth of the slot 40 are adapted to be turned down as indicated at 48 in Figure 7 to reinforce the shoulder portions 35, and the end portion 45' is adapted to be turned down to provide an arcuate end wall portion 51 for increasing the heat exchange contact between the fin plate and tubing.

Figures 9 and l0 illustrate the initial condition of the channel members wherein they comprise a flat planar body portion 55 with turned flanges 30a and 30h formed on sharp right angle corners relative to the body portion. The channel members or tube retainers may for example be .0040 inch thick spring red brass, and the body portion 55 may have `an outside span of about .360". The

anges may have an outsidelength of.'about,.125," and..

the length of the channel member may be about 20". The tubing may have a diameter of about 3/s" and the spacing betweenzthe flanges 48 at themouth ofthe notches may befaboutfAO while the spacing betweenpthe'walls of the nichesfatntheropposite sides of Ythe notches may be .43". The depth, of the notches, may; be about .37 plus 1/2 the diameter of the tubing. The length: 'of' the anges 43in. adirection transverse to the length of the inplates may be about .11 while` the length of the niches 46 may be about .26".

In assembling the retaining strips with the. tubek and iin structure vafter the tubes have been inserted in the respectivenotches, the strips may be mounted on die projections such as indicated at 60 having elongated recesses 61 of contour to conform to the external periphery of the tubing and with sharpedges. As illustrated in Figure 12, as the proiections 60 are moved into the notches, the planar portion 55 of the channel member is exed transversely into conforming contact with a portion of the periphery of the tubing, this exing urging the ange portions 39a and 31b to deflect out laterally into engagement with the turned edge anges 48 at the mouth of each notch. lt will be observed that the free ends 62 and 63 of the anges are bent due to engagement with the ilanges 48v and cannot assume their normal radial disposition relative to the tubing until the retainer is fully inserted into the notch and in fully conforming relation to the tubing, at which time the free ends 62 and 63 snap into the niches and into engagement with the shoulders 34, 35. The force exerted by the body portion, which tends to resume its normal planar configuration, now urges the free ends generally radially relative to the tubing, forcing them into the corners provided by the niches and ypreventing thefree ends 62 and 63 from becoming dislodgedv from engagement with the shoulders. Conversely, the body portion of the retainer in tending to resume its planar disposition presses the tubing rmly against the end anges 51 of the tin plates for good heat exchange contact therewith.

It will thus be appreciated that inviinal assembled condition, the retainer channels are in resilient tensioned condition between the shoulders 34, 35 and a peripheral portion of the tubing to maintain good heat exchange contact between thetubing and the fin plates. In other words, the shoulders 34, 35 are spaced from the end of the notch in the direction at right angles tothe length of the tins a distance less than the diameter of the tubing plus the length of the flanges, to require that the body portion of the retainer be wrapped about the periphery of the tubing and placed under a resilient tension before the flange free ends can engage against the shoulders at the outer ends of the niches;

It will be apparent that many modifications and variations may be effected Without departing from the scope of the novel concepts of the present invention.

We claim as our invention:

1. A plate and tube assembly comprising a length of tubing, a plurality of plates stacked in closely spaced overlying parallel relation with an exterior edge of each plate lying flush with corresponding exterior edges of the other plates and with a notch formed in each of said exterior edges in alignment with corresponding notches in the other plates, said length ot tubingextendin-g through the aligned notches of the respective plates, the margin of each notch being of U-shape and being dei-ined by interior edge portions of said plate integral with the plate, the interior edge portion of Isaid plate at'the inner closed end of each notch contacting a semi-peripheral portionof the tubing, and the interior edge portions-at the respective sides of each notch having niches therein extending outwardly from the `notch in the direction away from the center line of. the notch tol provide ,generally-right angle shoulders. of. substantial extent in theidirection at-'right gesmeed angles tothe. center.4 line of the notch` and facing .the

inner closed end of the notch, said niches having a substantially greater extent along the sides of the notch than the depth of said shoulders, said shoulders joining with adjacent edge portions of the plate defining the bottoms of the niches to define a corner at the ends of the shoulders remote from the center line of the notch, and a single continuous elongated channelretaining member which normally assumes a U-shape witha substantially planar body portion and right angle anges extending in the same direction from the opposite sides of the body portion and generally at right angles to the body portion, said -channel member extending through the aligned notches and havingits body portion transversely arced in conforming contact to a further portion of the periphery of the tubing at the side of the tubing nearest the open end of the notch, said arced body portion'contacting a` portionof the periphery of the tubing substan tially less than a semi-periphery thereof and the integral flange portions extending outwardly away from said tubing and forming acute angles of substantially less than with the center line of the notch and extending toward the open end of the notch and laterally away from the center line of the notch and terminating in free ends seated inthe corners between the shoulders and the adjacent edge portions of the niches, the transverse extent of the shoulders inwardly toward the center line ofl the f by interior edge portions of the plate, the interior edge portions of the plate at the inner `closed end of each' not-eh contacting the periphery of the tubing and leaving aportion of the. periphery of the tubing nearest the open end of the notch uncontacted thereby, and the interior edge portions at therespective sides of each notch providing shoulders spaced from said inner closed end of said notch, anda single continuous elongated channel retaining member of generally U configuration i-n crossseetion lextending through the aligned notches and including a transversely arced body portion of transverse arcuate extent substantially equal to the transverse diametric extent of said tubing, said arced body portion being in conforming contacting relation to the portionv of the periphery of the tubing nearest the open end of thev notch, said body portion having an arcuate transverse References Cited in the file of this patent UNITED STATES PATENTS Great Britain Feb. 20,' 1920 

